Effect of l-carnitine and emulsifier on growth performance, lipid profile, lipogenesis, and oxidative stress of broiler chickens raised at high altitude

High-altitude environments impose hypobaric hypoxia on broiler chickens, leading to pulmonary hypertension syndrome (PHS), oxidative stress, and impaired growth performance. l-carnitine, known for its role in energy metabolism and antioxidant properties, and emulsifiers, which enhance fat digestion, have the potential to mitigate these challenges. This study investigated the effects of l-carnitine and emulsifier supplementation, individually and in combination, on growth performance, lipid metabolism, oxidative stress, and gene expression in broilers raised at high altitudes. A total of 675 male broilers (Ross 308) were randomly assigned to nine dietary treatments, including control, l-carnitine (50 or 100 mg/kg), emulsifier (1 or 2 g/kg), and their combinations. Growth performance, carcass traits, serum lipid profiles, hepatic enzyme activities, oxidative stress markers, and gene expression (CPT1, CPT2, SOD1, iNOS) were evaluated over 42 days. Supplementation with l-carnitine and emulsifier improved weight gain and feed conversion ratio, and reduced feed intake. Carcass yield increased, and abdominal fat decreased significantly in treated groups. l-carnitine reduced serum cholesterol, triglycerides, and LDL while increasing HDL, indicating improved lipid metabolism. Oxidative stress markers, such as malondialdehyde (MDA), were reduced, and antioxidant gene expression (SOD1) was upregulated in l-carnitine-supplemented groups. Emulsifiers enhanced fat digestion, as evidenced by increased lipase activity and CPT1/CPT2 gene expression. Combined treatments showed no consistent additive effects. It is concluded that dietary supplementation with l-carnitine and emulsifiers enhances growth performance and lipid metabolism in broilers raised at high altitudes. While l-carnitine enhances antioxidant capacity, reduces oxidative stress, and improves cardiopulmonary health, emulsifiers do not directly affect oxidant and antioxidant status but optimize lipid parameters.